Proceedings Paper

This paper presents an overview of the very recent developments of the MCT infrared detector technology developed by
CEA-LETI and Sofradir in France for next generation of applications. New applications require high sensitivity and dual
band detectors.
The Avalanche PhotoDiodes (APD) technology opens new interesting fields of investigation for low flux applications
and fast detectors for laser imaging. IR sensors for this type of application are synchronized with eye-safe lasers, and
have to detect a weak signal backscattered from the target on the order of 10 photons per pulse. They also have to be
able to operate with a very short integration time, typically one hundred nanoseconds, in order to gate the backscattered
signal around the target. In partnership with Sofradir, CEA/LETI (France) has developed high quality MCT avalanche
photodiodes satisfying these requirements. In parallel, specific studies have been carried out at the Read-Out Circuit
level to develop optimized architectures. Thanks to these advances, a new Integrated Dewar Detector Cooler Assembly
has been developed. This new product presented in this paper is the first step in a road-map to address low flux infrared
sensors in the next few years.
In parallel, the development of dual-band infrared detectors has been the core of intense research and technological
improvements for the last ten years. New TV (640 x 512 pixels) format detectors of 24μm pixel pitch is available. It is
proposed with MWIR/MWIR or MWIR/LWIR dual band sensitivity integrated in dedicated tactical Dewars. At present,
focused on pixel pitch reduction, Sofradir is carrying out optimization of the materials quality, photodiode design as well
as flip-chip bonding process. 20 μm pixels have demonstrated dual color key performances (quantum efficiency, optical
fill factor, and pixel operability) in accordance with mono-spectral structures. Results are presented in this paper.